74 



THE BONES. 



pletely closes the excavatioh which coucurs to form the maxillary sinus. In the skeleton there 

 is also found behind, and at the base of this turbinated bone, a vast opening which is totally 



closed in the fresh condition by the pituitary membrane. 

 The maxillary sinus is not prolonged in its interior. 

 In the smaller Euminants, tlie cavity of the sinus is 

 closed by the maxillary turbinated bone in a more 

 complete manner than in the Ox. 



B. Camel. — The ethmoidal turbinated bone is 

 very small. Otherwise it is as in the other Ruminants. 



C. Pig. — The same arrangement as in tlie Sheep 

 and Goat, except that the bones are mucli longer and 

 less fragile. 



D. Carnivora.— These bones in tlie Dog and Cat 

 are particularly distinguished for their numerous cou- 

 volutions. Neither participate in the formation of 

 the frontal or maxillary sinuses; the latter is not in 

 any way closed by the maxillary turbinated bone, but 

 opens into the nasal cavity by a large gaping aperture. 



E. Rabbit. — The bones are arranged as in the 

 Dog, but the folds are less numerous. 



9. VoMEE (Figs. 34, 38). 



This, a single bone, elongated from above 

 to below, flattened on both sides, and extending 

 on the median line from the body of the 

 sphenoid to the premaxillary bone, offers for 

 study two lateral faces, two borders, and two 

 extremities. 



The faces are smooth, plane, and covered 

 by the nasal membrane. The anterior border 

 is channeled for the whole of its length by a 

 deep groove, which receives the posterior border 

 of the cartilaginous septum of the nose. The 

 posterior border is sharp and smooth in its 

 upper half, which separates the two guttural 

 openings of the nasal cavities : it is thick and 

 slightly denticulated for the remainder of its 

 extent, and rests on the median suture resulting 

 from the union of the two supermaxillary 

 bones. The superior extremity is provided, in 

 its middle, with a notch which divides it into 

 two lateral prolongations shaped like a cat's 

 ears {wings of the vomer) ; it articulates with 

 the inferior sphenoid, ethmoid, palatine, and 

 pterygoid bones. The inferior extremity rests 

 on the prolongations of the premaxillae. 



This bone is entirely compact, and is 

 developed from one centre of ossification. 



MEDIAN AND VERTICAL SECTION OF 

 THE ox's HEAD. 



X, Condyloid foramen; 1', posterior ori- 

 fice of the occipital lateral canal 

 joining the parieto-temporal canal 

 in front ; 2, internal auditory hiatus ; 

 3, anterior foramen lacerum ; 4, pos- 

 terior ditto ; 5, iutra-cranial orifice 

 of the parieto-temporal canal ; 6, 6, 

 median bony plate separating the 

 frontal sinuses ; 7, lamina which iso- 

 lates the sphenoidal sinus; 8, lamina 

 partitioning the palatine portion of 

 the maxilliary sinuses ; 9, oval fora- 

 men ; 10, optic fossa; 11, vomer; 

 12, pterygoid bone ; 1.3, large open- 

 ing leading into the maxillary sinus, 

 and which, in the fresh state, is closed 

 by the pituitary membrane ; 14, max- 

 illary turbinated bone; 15, ethmoidal 

 turbinated bone; 16, great ethmoidal 

 cell. 



Differential Characteks in the Vomer of 



OTHER Animals. 

 A. Ox, Sheep, Goat. — This is a very wide and 

 thin bone, resting only on the lower half of the median 

 suture of the premaxillaries (Fig. 43). 

 B. Camel.— Wider in its upper part than in the Ox, the vomer reaches, outwardly, the 



